Modeling Greenhouse Gas Emissions from Activated Sludge Processes

Snowling, Spencer; Montieth, Hugh; Schraa, Oliver; Andres, Hank

doi:10.2175/193864706783761482

Cited by 2 publications

(1 citation statement)

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“…The CO 2 dynamics can be more accurately described when they are included in a simulation model. Although the biochemical mechanisms of N 2 O production during biological nitrogen removal have also been included in activated sludge models in some recent studies (Hiatt and Grady, 2008;Houweling et al, 2011), probably as a result of the relatively clear understanding on the processes forming CO 2 , few studies have bothered to extend the activated sludge models for CO 2 (Snowling et al, 2006). In most studies, biogenic CO 2 has been estimated by simple empirical models, which account for GHG emissions resulting from biodegradation of organic matter, endogenous respiration, and anaerobic digestion using a simple mass balance method (Corominas et al, 2012;Flores-Alsina et al, 2011;Monteith et al, 2005;Ni et al, 2012;Sahely et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Numerical Modeling of Greenhouse Gas Emissions from Water Resource Recovery Facilities

Kim

Bowen

Kinnear³

2015

Water Environment Research

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A numerical model was developed to comprehensively predict greenhouse gas (GHG) emissions from water resource recovery facilities. An existing activated sludge model was extended to include a nitrifier-denitrification process and carbon dioxide (CO₂) as a state variable. The bioreactor model was coupled to a process-based digester model and an empirical model of indirect CO₂emissions. Direct emissions were approximately 90% of total GHG emissions for a plantwide simulation using the Modified Ludzack-Ettinger process. Biogenic CO₂, nitrous oxide (N₂O), and methane (CH₄) represented 10, 43, and 34% of total emissions. Simulating a dissolved oxygen controlled closed-loop system reduced both sensitivity and uncertainty of GHG emissions. Nitrous oxide emissions were much more sensitive under different design and operating conditions compared to CH₄and CO₂, indicating a significant mitigation potential. An uncertainty analysis found that the uncertainty in GHGs emissions estimates could be significant. Nitrous oxide emissions dominated in both magnitude and uncertainty.

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